In general, aerogel is a high porosity material having high porosity of about 90% to about 99% in solids that are known up to date. A silica precursor solution is subjected to sol-gel polymerization reaction to from gel, and then, drying process is performed on the formed gel under supercritical or atmospheric conditions to obtain the aerogel. That is, aerogel has a pore structure filled with air.
The above-described aerogel is lightweight and has physical properties such as heat insulation and sound absorption due to the unique pore structure in which 90% to 99% of an internal space is empty. The greatest advantage of the above-described advantages is the high heat insulation having thermal conductivity of 30 mW/m.k or less, which is significantly lower than thermal conductivity of 36 mW/m.k that is thermal conductivity of an organic insulation material such as conventional Styrofoam and the like.
However, the aerogel according to the related art has problems that the sheet has nonuniform thickness and poor heat insulation and durability.